OFFSET
0,3
COMMENTS
The coefficients of the polygonal polynomials are antidiagonals of A139600.
FORMULA
a(n) = 2^n * Sum_{k=0..n} A139600(n, k) * 2^(-k).
a(n) = [x^n] x*(-4*x^2 + 3*x - 1) / ((1 - 2*x)^2*(x - 1)^3).
a(n) = 8 + 4*n + n^2 + (n-4) * 2^(n+1). - Vaclav Kotesovec, Feb 21 2023
MAPLE
gf := (x*(-4*x^2 + 3*x - 1)) / ((1 - 2*x)^2*(x - 1)^3):
ser := series(gf, x, 32): seq(coeff(ser, x, n), n = 0..30);
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, Feb 13 2023
STATUS
approved